Michigan State Department of Agriculture authorities recently revealed that they quarantined a dairy herd in Alcona County on Nov. 27 due to suspected bovine tuberculosis (TB) infection. At question is a 5-year-old cow from which researchers isolated a suspicious organism. More tests are currently underway that will provide a more definitive diagnosis — final results are expected in mid-January.

This herd tested negative for the disease in 1998, 2000 and 2001, but tests last August revealed the current problem. This case is particularly troublesome because there has been significant movement of cattle from this farm to other operations in the area. State officials are tracking animal movement and contacting people who have had cattle sales and purchases with the dairy.

The affected herd resides in one of the "infected" counties designated by the state’s TB eradication program. The four counties where the disease was first discovered are classified as infected, while the six surrounding counties are classified as the surveillance zone as a buffer around the disease. The state’s remaining 73 counties are classified as disease free. The zones may only be changed after public comment and a thorough investigation that identifies significant infection risk and disease prevalence in the region.

More than 20 cattle herds in Michigan have been identified as TB-positive since the mid-1990s and destroyed to prevent further spread of the disease.

For more information about bovine TB or Michigan’s eradication program, go to the Web site at: www.bovinetb.com

The Detroit News, Wisconsin Farm Report